Examine source code of YT smooth caret

{
  "name": "YT smooth caret",
  "description": "A smooth caret extension for YouTube",
  "version": "1.0",
  "manifest_version": 2,
  "content_scripts": [
    {
      "matches": [
        "*://*.youtube.com/*"
      ],
      "js": [
        "main.js"
      ]
    }
  ],
  "host_permissions": [
    "<all_urls>"
  ],
  "permissions": [
    "activeTab"
  ],
  "browser_action": {
    "default_popup": "gui.html"
  },
  "browser_specific_settings": {
    "gecko": {
      "id": "{445f2895-f3fb-4425-ad2a-7cbb2b331c75}"
    }
  }
}